• 대한수학교육학회지:학교수학
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• 제9권1호
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• pp.1-12
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• 2007

유리수의 개념에 대한 이해를 확립하고 실수로의 확장 가능성을 탐색하는 수학 8단계 학습에서 제시되는 '유리수와 순환소수와의 관계'에 대하여 교과서 별로 서로 다른 내용을 담고 있어 많은 학습자들이 혼란을 겪고 있다. 이 연구에서는 순환 소수에 대한 교육과정, 교과서, 평가문항을 분석하여 순환소수 지도에서의 문제점을 찾고 그에 따른 바람직한 해결방안을 모색하였다. 대안으로서, '0을 순환마디로 사용할 것'과 유한소수의 정의를 '0이 순환하는 소수'로 할 것을 제안하였다. 이를 바탕으로 '모든 유리수는 순환소수로 나타낼 수 있으며, 모든 순환소수는 유리수로 나타낼 수 있다'는 관계의 지도를 해결방안으로 삼았다.

• 대한수의학회지
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• 제63권4호
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• pp.35.1-35.10
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• 2023

Non-human primate (NHP) research faces challenges due to zoonosis risk and complex veterinary management yet lacks standardized guidelines for animal care. Therefore, we developed an advanced veterinary management protocol for NHP quarantine, anesthesia, and postoperative care. Three female 4 to 5-year-old cynomolgus monkeys were anesthetized and underwent various tests, including body weight, temperature, blood tests, urinalysis, microbiological monitoring, and physical and dental examinations. Ivermectin and medicated baths were administered to eradicate ectoparasites and endoparasites, and testing was repeated 30 days later. Following quarantine, we performed computed tomography and anesthesia maintenance for mastoidectomy. To relieve pain and maintain body weight, we administered tramadol intramuscularly 4 times/day for 3 days and meloxicam subcutaneously twice daily for 14 days. Feed replacements were provided. During the 33-day quarantine period, physical examinations revealed no abnormalities indicative of infectious diseases, and no specific clinical symptoms were observed. Through a preliminary test of anesthesia time, we selected ketamine 4 mg/kg + medetomidine 50 ㎍/kg for short experiments such as computed tomography, and ketamine 8 mg/kg + medetomidine 50 ㎍/kg for intubation. Ten days after mastoidectomy, NHPs consumed 100 kcal/kg and recovered their body weight. This study offers advanced veterinary management guideline for NHP research. Such protocols can lead to more standardized and ethical practices in NHP research, thereby enhancing the quality of studies on NHPs and the translation of findings to human health and disease.

• 한국방사선학회논문지
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• 제17권6호
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• pp.819-825
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• 2023

흉부 CT 검사 조건 중 관전압을 100, 80 kVp, 재구성 알고리즘을 FBP, ASIR-V, DLIR로 변화 적용하여 검사 선량과 화질 변화를 비교 분석해 보았다. 그 결과 기존 관전압 보다 낮은 관전압인 100 kVp 에서 ASIR-V, DLIR 적용 시 선량을 낮추면서 120 kVp, FBP 적용 시와 가장 유사한 화질로 구현. 특히, DLIR 재구성 영상은 모든 관전압에서 SNR, CNR이 우수하였다. 또한, SSIM 지수가 1에 가장 근사하게 분석되어 원본 영상과 가장 유사도가 높은 것을 알 수 있었다. 따라서 반복적으로 흉부 CT 검사를 시행하는 경우 DLIR 적용은 검사 선량을 약 29.7% 감소시킬 수 있어 CT 검사의 가장 큰 문제점인 검사로 인한 피폭을 일부 해결하는 데 도움을 줄 수 있을 것으로 사료된다.

• Toxicological Research
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• 제23권1호
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• pp.87-96
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• 2007

Single and repeated-dose toxicity of anti-diabetic herb extract microcapsule (ADHEM) were evaluated according to Toxicity Test Guidelines of Korea Food and Drug Administration using Sprague-Dawley rats. For single-dose toxicity test, kneading ADHEM with sterilized water were administered orally once at dose levels of 0 and 2,000 mg/kg and examined for 14 days. No dead animals, clinical signs and abnormal necropsy findings were observed and also no significant difference in body weights was found. Therefore, the $LD_{50}$ of ADHEM was considered to be higher than 2,000 mg/kg in both male and female rats. For repeated-dose toxicity test, ADHEM were mixed with powder fodder and administerd orally for 28 days at dose levels of 0, 500, 1000 and 2000 mg/kg/day. No dead animals, clinical signs and significant difference in body weights were found. In hematology and serum biochemistry, all values were included within the normal ranges. In relative organ weights, kidney or liver were significantly increased in the 500, 1000 or 2000 mg/kg/day male groups, uterus was significantly increased in the 500 mg/kg/day female group and left adrenal glands were significantly decreased in the 2000 mg/kg/day female group. In histopathological examinations, vacuolation and microgranuloma in the liver, chronic progressive nephropathy and inflammation in the kidney were observed in the 500, 1000 or 2000 mg/kg/day both male and female groups. Therefore, the no observed adverse effect level (NOAEL) of ADHEM was considered to be lower than 500 mg/kg/day in both male and female rats.

• Journal of Oral Medicine and Pain
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• 제36권2호
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• pp.131-137
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• 2011

신경 손상 정도를 평가하기 위한 정량적감각평가(Quantitative Sensory Testing, QST) 방법 중 하나인 전류인지역치(Current Perception Threshold, CPT) 검사는 비교적 짧은 시간 내에 3가지 감각신경, 2000 Hz(A${\beta}$ fiber), 250 Hz(A${\delta}$ fiber), 5 Hz(C fiber)에 대한 기능을 평가 할 수 있다고 알려져 있지만, 그 재현성에 대해서는 여전히 상반된 견해가 존재한다. 본 연구는 CPT 검사의 재현성을 확인하고, 재현성을 향상시키기 위한 방법을 모색하고자 하였다. 건강한 남성 지원자 10명(평균 22.4세)을 대상으로 3주 동안 1주일 간격으로 2명의 검사자가 하악신경 영역을 각각 좌우로 나누어 3회 측정하여 비교 하였다. 3주에 걸친 측정 실험에서 2000 Hz(A${\beta}$ fiber)의 CPT는 3회 모두 좌우 측정치가 차이를 보인 반면(p<0.05), 250Hz(A${\delta}$ fiber)는 1회만 유의한 차이를 보였고(p<0.05), 5 Hz(C fiber)는 유의한 차이를 보이지 않았다. 좌우를 나누어 3회의 실험을 비교했을 때 모든 신경 검사에서 첫 회의 CPT가 가장 낮았으며, 250 Hz(A${\delta}$ fiber)와 5 Hz(C fiber)의 CPT는 첫 번째 실험과 나머지 실험사이에 유의한 차이가 있었고(p<0.05), 두 번째 실험 이후로 유의한 차이가 없었다. 상기의 결과로 보아 2000 Hz(A${\beta}$ fiber)의 CPT를 이용한 좌우 신경의 기능 비교는 적절하지 않은 반면, 250 Hz(A${\delta}$ fiber)와 5 Hz(C fiber)에서는 좌우 비교가 가능할 것으로 생각된다. 또한 반복 측정을 통해 250 Hz(A${\delta}$ fiber)와 5 Hz(C fiber)의 CPT 검사의 재현성을 높일 수 있을 것으로 판단된다.

• Toxicological Research
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• 제34권1호
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• pp.55-63
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• 2018

As a part of general toxicity studies of Enterococcus Faecalis 2001 (EF 2001) prepared using heat-treatment bacillus mort body EF 2001 in mice, this study examined the toxicity of EF 2001 in single and repeated administrations following the previous report in order to apply this product to preventive medicine. The safety of oral ingestion of EF 2001 was examined in 6-week-old male and female ICR mice with 1,000 mg/kg, 3,000 mg/kg and 5,000 mg/kg body weight/day administrated by gavage of the maximum acceptable dose of EF 2001. The study was conducted using distilled water as a control following the methods for general toxicity studies described in the "Guidelines for Non-clinical Studies of Pharmaceutical Products 2002". As a control, 1) observation of general conditions, 2) measurement of body weight, 3) determination of food consumption, 4) determination of water consumption, 5) blood test and urinalysis and 6) pathological examination were performed for the administration of EF 2001. Mice received EF 2001 for 13 weeks and results were compared with those of the control group that received distilled water. The results of the above examinations revealed no significant differences between control and EF 2001 groups for both males and females. Thus, no notable toxicity was confirmed with single and repeated oral administrations of EF 2001. Oral administration in the above doses did not result in abnormal symptoms or death during the observation period. No abnormalities in blood cell count or organ weights were seen. Without any evidence of toxicity to cells and organs, EF 2001 is speculated to not adversely affect living organisms. The 50% lethal dose of EF 2001 with oral administration in mice is estimated to be greater than 5,000 mg/kg body weight/day for both male and female mice. Therefore, $LD_{50}$ value for animals was 5,000 mg/kg or more.

• 한국식생활문화학회지
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• 제34권6호
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• pp.801-809
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• 2019

Abeliophyllum distichum Nakai is a deciduous shrub of a flowering plant in Oleaceae. It is an important plant resource and consists of only one species in the entire world. A. distichum Nakai is well known an edible, medicinal herb in its habitat districts, but the toxicological evaluation for the safe use of its extract is still insufficient. The study characterized the toxicity of an Abeliophyllum distichum Nakai ethanol extract in Sprague-Dawley (SD) rats and determined the safe dosage levels in a 13 weeks toxicity study. Abeliophyllum distichum Nakai ethanol extract was orally administered once daily for 2 weeks at 0, 500, 1,000 and 2,000 mg/kg/day to male and female SD rats. while recording the clinical signs of toxicity, body weight, food intake/consumption, eye test and urine analysis. Only the total protein frequency in the urine of male SD rats (p<0.05), the right ovary of the 500 mg/kg group (p<0.01) and the right adrenal gland of the 1,000 mg/kg group (p<0.05) in the female rats showed statistically significant changes. But no toxic effects were noted from repeated-dose administration of the Abeliophyllum distichum Nakai ethanol extract in the SD rats during the observation period. The post-mortem examinations showed no test substance-mediated changes. The hematological analysis and clinical blood chemistry data demonstrated no toxic effects from repeated-dose administration of Abeliophyllum distichum Nakai ethanol extract in the SD rats during the observation period. Based on these results, this data suggests that a dose of 1,000 mg/kg/day is a highest treatment to administer when conducting a further 13 weeks toxicity study.

• Biomolecules & Therapeutics
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• 제6권2호
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• pp.182-190
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• 1998

DA-3585 is a recombinant human erythropoietin produced by Dong-A pharmaceutical Co. Ltd. using recombinant DNA technique. Recently, recombinant human erythropoietin (rHu-EPO) has been used to treat various types of anemia. In this study, we examined acute and subacute toxicity of DA-3585 in rats. DA-3585 was intravenously administered to rats at dose levels of 0, 6,250, 12,500 and 25,000 lU/kg for single dose toxicity study and at dose levels of 0,100,500 and 2,500IU/kg daily for 4 week-repeated dose toxicity study. In the single dose toxicity study, there were no death, clinical signs and changes in body weight gain related to the treatment. Necropsy revealed no evidence of toxicity related to DA-3585, In the repeated dose toxicity study, all the rats survived throughout the study. There were no treatment-related changes in clinical signs, food and water intake, and body weight. Hematological examination showed increases in the number of erythrocytes, hemoglobin concentration, hematocrit value and mean corpuscular volume, and decrease in the number of platelet in 500 and 2,500 lU/kg dosed groups. Extramedullary hematopoiesis in the spleen and erythroid hyperplasia in the bone marrow were noted as treatment-related histological changes. Toxicologically significant changes were not observed in blood biochemistry, urinalysis, organ weights and in any other examinations. The treatment-related changes observed in this study were hematological or histological changes associated with pharmacological effects of DA-3585. On the basis of the results of this study, LD5n value of DA-3585 was above 25,000 lU/kg and the no-observed-adverse-effect-level was estimated to be 100 lU/kg.

• Biomolecules & Therapeutics
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• 제6권2호
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• pp.171-181
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• 1998

DA-3585, a biosynthetic recombinant human erythropoietin has been developed as a treatment for anemia associated with chronic renal failure in Dong-A pharmaceutical Co. Ltd. This study was carried out to assess its acute and subacute toxicities in rabbits. DA-3585 was intravenously administered to rabbits at dose levels of 6250, 12500 or 25000 lU/kg for single dose toxicity study and at dose levels of 100, 500 or 2500 lU/kg/day for 4-week repeated dose toxicity study. In the acute toxicity study, dose up to 25000 lU/kg had no adverse effect on the behavior or body weight gain. Pathological examinations revealed no abnormal gross lesions related to DA-3585. In the subacute toxicity study, all animals survived until termination of treatment. DA-3585 had no influence on clinical signs, food and water intake or on body weight changes. Hematological examination showed increases in the number of RBC, hemoglobin contents and hematocrit values with a dose dependent manner in the animals treated with DA-3585. Histopathological examination revealed erythroid hyperplasia in the bone marrow and extramedullary hematopoiesis in the liver. The changes detected in the hematological and histopathological examination presumably represent exaggerated pharmacological effects of erythropoietin. The NOAEL (no-observed-adverse-effect-level) of DA-3585 was estimated to be 100 lU/kg/ day under this study condition.

• Journal of Korean Neurosurgical Society
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• 제58권1호
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• pp.30-35
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• 2015

Objective : The clinical and pathological characteristics of 10 cases of cerebral amyloid angiopathy (CAA)-related cerebral lobar hemorrhage (CLH) that was diagnosed at autopsy were investigated to facilitate the diagnosis of this condition. Methods : The clinical characteristics of 10 cases of CAA-related CLH were retrospectively reviewed, and a neuropathological examination was performed on autopsy samples. Results : The 10 cases included two with a single lobar hemorrhage and eight with multifocal lobar hemorrhages. In all of the cases, the hemorrhage bled into the subarachnoid space. Pathological examinations of the 10 cases revealed microaneurysms in two, double barrel-like changes in four, multifocal arteriolar clusters in five, obliterative onion skin-like intimal changes in four, fibrinoid necrosis of the vessels in seven, neurofibrillary tangles in eight, and senile plaques in five cases. Conclusion : CAA-related CLHs were located primarily in the parietal, temporal, and occipital lobes. These hemorrhages normally consisted of multiple repeated CLHs that frequently bled into the subarachnoid space. CAA-associated microvascular lesions may be the pathological factor underlying CLH.